Fiber size, sized reinforcements, and articles reinforced with such reinforcements

ABSTRACT

The present invention relates to fiber-size compositions for coating glass or other reinforcing fiber materials that are used in the manufacturing of composites. The fiber-size composition contains at least about 4% by weight of a polyvinylpyrrolidone film former, at least one lubricant and a coupling agent. The sizing composition gives the fibers desirable properties such as high strength, improved flexibility, fuzz formation resistance, and fiber smoothness and softness.

TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION

The present invention relates to fiber-size compositions for coating glass or other reinforcing fiber materials that are used in the manufacturing of composites. The sizing composition gives the fibers desirable properties such as high strength, improved flexibility, fuzz formation resistance, and fiber smoothness and softness.

BACKGROUND OF THE INVENTION

Glass fibers are useful in a variety of technologies. For example, glass fibers are commonly used as reinforcements in polymer matrices to form glass fiber reinforced plastics or composites. Glass fibers have been used in the form of continuous or chopped filaments, strands, rovings, woven fabrics, nonwoven fabrics, meshes, and scrims to reinforce polymers. It is known in the art that glass fiber reinforced polymer composites possess higher mechanical properties compared to unreinforced polymer composites, provided that the reinforcement fiber surface is suitably modified by a sizing composition. Thus, better dimensional stability, tensile strength and modulus, flexural strength and modulus, impact resistance, and creep resistance may be achieved with glass fiber reinforced composites.

Chopped glass fibers are commonly used as reinforcement materials in reinforced composites. Conventionally, glass fibers are formed by attenuating streams of a molten glass material from a bushing or orifice. The glass fibers may be attenuated by a winder which collects gathered filaments into a package or by rollers which pull the fibers before they are collected and chopped. An aqueous sizing composition, or chemical treatment, is typically applied to the fibers after they are drawn from the bushing. After the fibers are treated with the aqueous sizing composition, they may be dried in a package or chopped strand form.

Chopped strand segments may be mixed with a polymeric resin and supplied to a compression- or injection- molding machine to be formed into glass fiber reinforced composites. Typically, the chopped strand segments are mixed with pellets of a thermoplastic polymer resin in an extruder. In one conventional method, polymer pellets are fed into a first port of a twin screw extruder and the chopped glass fibers are fed into a second port of the extruder with the melted polymer to form a fiber/resin mixture. Alternatively, the polymer pellets and chopped strand segments are dry mixed and fed together into a single screw extruder where the resin is melted, the integrity of the glass fiber strands is destroyed, and the fiber strands are dispersed throughout the molten resin to form a fiber/resin mixture. Next, the fiber/resin mixture is degassed and formed into pellets. The dry fiber strand/resin dispersion pellets are then fed to a molding machine and formed into molded composite articles that have a substantially homogeneous dispersion of glass fiber strands throughout the composite article.

It has been determined that sizing compositions containing a high molecular weight film-former, such as a polyvinylpyrrolidone having a molecular weight of 1.6 million, results in a stiff glass fiber strand having extremely high fuzz. This is a result of the film-former forming a brittle film which leads to fiber breakage as it crosses contact points in the manufacturing operation.

SUMMARY OF THE INVENTION

The above problems are solved and objects met by the present invention which features a fiber-size composition comprising a) low molecular weight polyvinylpyrrolidone, b) a coupling agent, c) one or more lubricants, and d) optional additives. The fiber-size composition is typically aqueous based and is water soluble.

The coupling agent has at least one group that is reactive with a fiber and a second group that is reactive with the resin matrix. Both of these groups tend to be hydrophilic and usually soluble in water. Typically, the coupling agent is a silane.

Optional additives may be added to the fiber-size composition, such additives include, but are not limited to wetting agents, lubricants, surfactants, and antifoam agents. An additional polyurethane film-former can also be used in the fiber-size composition to improve the processing characteristics of the size composition and is also useful in maintaining fiber integrity during the processing of coated fibers. Polyurethane provides good adhesion to a variety of matrix resin polymers, is UV stable, hyrodlytically stable and easily dispersible in aqueous systems.

Glass fibers are typically coated with the fiber-size composition as part of the fiber filament formation process. By coating the fiber with the size composition early in its formation stage, the fiber size coating protects the filaments from abrasion and breakage as the filaments are formed into fibers and wound or chopped for further processing.

The fiber-size composition can be applied to all glass fibers including E-glass (a borosilicate glass) as well as boron-free fibers. The boron-free fibers can also be essentially free of moieties such as F₂, TiO₂, SO₃, and combinations of them. A boron-free glass fiber that can be advantageously coated with the fiber-size composition of the present invention. Such boron-free glass fibers are manufactured by Owens Coming (Toledo, Ohio) under the name ADVANTEX®.

After the fiber is coated with the fiber-size composition, it is used as part of a compounding formulation that includes the size coated (reinforcing) fiber and a matrix resin. The matrix resin can be selected from a wide variety of plastics including polyolefins, polyesters, polyacetals, polyamides, polyacrylamides, polyimides, polyethers, polyvinylethers, polystyrenes, polyoxides, polycarbonates, polysiloxanes, polysulfones, polyanhydrides, polyimines, epoxies, polyacrylics, polyvinylesters, polyurethane, maleic resins, urea resins, melamine resins, phenol resins, furan resins, polymer blends, polymer alloys and mixtures of them.

The compounding formulation can also contain one or more compounding agents such as coupling agents, antioxidants, pigments, antistats, fillers, flame retardants and other additives. Preferably the matrix resin is a long-fiber thermoplastic polyamide.

The compounding formulation is then typically processed to form pellets that are then injected molded to form the desired composite article.

The present invention also features a method of preparing reinforcing fibers and then using them to form a composite article.

After the fiber-size composition is prepared, it is contacted with fibers after which the fiber-size composition is allowed to solidify on the fibers to form the reinforcing fibers After the reinforcing fibers are prepared they are mixed with a matrix resin to form a composite formulation. The composite formulation can also contain coupling agents, antioxidants, pigments, antistats, fillers, and flame retardants. The composite formulation is then processed to form a composite article.

It is an object of the present invention is a sizing composition useful to prevent fuzzing comprising substantial amount of a polyvinylpyrrolidone (PVP) film former.

Another object of the invention is a strand which incorporates the PVP sizing. The sized strand is preferably made by the application of the a sizing composition containing PVP to a plurality of individual fiber filaments which are then gathered into a strand.

Another object of the invention are pellets which incorporate the sizing. The pellets are preferably made by impregnating the strand with a synthetic resin, cooling to form an impregnated strand, and chopping the impregnated strand to form the pellets.

Yet another object of the invention is a reinforced resin composite incorporating the sizing. The composite comprises a fiber reinforcing material dispersed in a synthetic resin matrix. The mixed is preferably made by directly consolidating the pellets.

Yet another object of the invention is a fiber-size composition that is particularly well-suited for use in long-fiber thermoplastic applications. Fiber-reinforced thermoplastic polymer structural components are most commonly manufactured from long fiber thermoplastic (LFT) granulates (pellets), glass mat thermoplastic (GMT) sheets, or pultruded sections. Long fiber-reinforced granulates typically consist of glass fiber bundles encapsulated with a thermoplastic through a cable coating or a pultrusion process. LFT granulates can be injection molded but are more commonly extrusion compression molded in order to preserve fiber length in the finished product.

The injection-moldable pellets thus contain fully wetted fibers equal in length to the pellet—typically 1 to 25 mm. This compares to 0.75 mm to 1.5mm. fiber lengths used in conventional, short-fiber products. As is well-known, mechanical properties of long-fiber compounds are improved dramatically over those of the short-fiber compounds.

Polymer components reinforced with fibers may also be manufactured using continuous in-line extrusion methods known in the art. Such methods involve the plastication of a polymer in a first single screw extruder from which the output is fed to a second single screw extruder. Fibers are introduced in the polymer melt in the second extruder either in chopped-segmented form or as continuous strands under a predetermined tension. The fiber-reinforced polymer compound is fed into an accumulator and then applied automatically or in a separate step to a compression molding tool wherein the fiber-reinforced polymer compound is shaped as required for a particular application. Alternatively, the fiber-reinforced polymer compound may be continuously extruded onto a conveyor and sectioned thereupon. The conveyor delivers the sectioned fiber-reinforced polymer compound to a placement assembly which removes the sectioned compound from the conveyor and places the compound upon the compression molding tool.

As used here, the term “size” or “sizing” refers to a coating that is applied initially to forming filaments of a fiber for the purpose of protecting the fiber from abrasion breakage of the fibers during further processing of the fibers and subsequently promoting the adhesion between the fibers and the materials which they reinforce. While some physical binding between filaments may occur when the filaments are bundled into threads, it is essential that the sizing not interfere with the dispersion of the fibers in the matrix into which h the fibers are incorporated. That is, the sizing should not have a tendency to agglomerate the threads, especially when incorporated into a matrix composition. This is in contrast to a “binder” where the formulation promotes the binding of threads to each other at their intersection (crossing points) in such forms as mats, fabrics and nonwovens through the polymerization of the binder while it is in contact with the fibers. One of the purposes of a size is to coat the entire filament in order to protect the filaments and fibers during initial formation of the filaments and fibers and in their subsequent processing.

In a size, the emphasis is on bond formation between moieties already existing on components in the size composition and moieties found on the glass and between moieties found on components in the size composition and moieties found in the matrix resin typically with minimal polymerization of the components found in the size composition. A size typically solidifies on the fiber principally as a result of physical water removal whereas a binder is designed for a chemical (typically polymerization) reaction that gives a stronger fiber to fiber binding.

The foregoing and other objects, features and advantages of the invention will become apparent from the following disclosure in which one or more preferred embodiments of the invention are described in detail. It is contemplated that variations in procedures may appear to a person skilled in the art without departing from the scope of or sacrificing any of the advantages of the invention.

DETAILED DESCRIPTION AND EMBODIMENTS OF THE INVENTION

The present invention comprises a fiber-size composition having at least about 4% by weight of a polyvinylpyrrolidone (PVP) film former, at least one lubricant, and a coupling agent that improves the sizing reinforced fiber materials used in the manufacture of fiber-reinforced composites. The fiber-size composition provides improved short-term mechanical performance of fiber-reinforced composites such as increased strength and reduced fuzzing of the strand. Optionally, the fiber-size composition may also contain an additional polyurethane film former and conventional additives such as wetting agents, pH adjusters, etc. The fiber-size composition provides improved long-term mechanical performance of the composite such as increased resistance to creep and fatigue.

The PVP film former is a low molecular weight film former having a molecular weight in the range of about 10,000 to about 70,000. Use of a low molecular weight film former results if a more flexible coating on the glass fiber strand. Typical PVP film formers include K15 and K30 film formers available from ISP International, Wayne, N.J. The fiber size composition includes at least about 4% by weight of the PVP film former, typically between about 4% to about 7% by weight based on the sum of fiber size constituents making 100%. Using a substantial amount of PVP film former results in many improved properties of the glass fiber strand.

A wide variety of coupling agents are known in the art most of which most are silicon-based “silane” coupling agents. The typical coupling agent is a silane represented by the formula X_(n)—Si—Y_(4-n), where X is an acid reactive group and Y is a fiber reactive group, and n is preferably 1 but may be 2 or 3. Typically Y is an alkoxy that is hydrolyzed to a hydroxyl group in the fiber-size composition. X is typically an alkyl amino group but other functional groups are commercially available. Aminosilanes are commercially available from OSi Specialties, Inc., located in Tarrytown, N.Y., United States of America, Dow Corning, Inc. located in Midland, Mich., United States of America, or Degussa-Huls AG located in Frankfurt, Germany. A preferred amino silane coupling agent is gamma-aminopropyltriethoxysilane commercially available under the trade name A-1110 from OSi Specialties, Inc.

The coupling agent is generally included in the fiber-size composition at a concentration of about 1.0% to about 15% by weight. Preferably, the coupling agent is used in an amount of from about 0.25% to about 7.0 percent by weight. Most preferably, the amount is between about 0.5% to about 2.0% by weight.

Lubricants which may be used include lower molecular weight polyethylene glycol (PEG) lubricants such as those sold under the tradenames, PEG 400MO (polyethylene glycol monostearate) and PEG 200MO (polyethylene glycol monostearate). Amounts of PEG lubricants present in the fiber-size composition range from about 2.0% to about 3.5% by weight.

An additional lubricant may be added to the fiber-sizing composition such as a polyethyleneimine polyamide salt lubricant. Such a lubricant is EMERLUBE 6760 (available from Emery Corp.). The additional lubricant is present in the fiber-size composition in an amount of from about 0.45% to about 0.70% by weight.

Optionally, an additional polyurethane film former is present in the fiber-size composition. Such a polyurethane film former is sold under the name HYDROSIZE U6-03 manufactured by Hydrosize Technologies, Raleigh, N.C. The polyurethane film former is present in the fiber-size composition in an amount of from about 1.0% to about 4.0% by weight.

In particular, it is preferred that pH of the size composition generally fall within a pH range of between about 4 to about 6.5. However the pH of the size composition may be adjusted to facilitate the compatibility of the fiber-size ingredients through the addition of one or more pH adjusters. For example, small amounts of a weak acid, such as acetic acid, may be added to the fiber-size to adjust the pH. Acetic acid may be present in the size composition in an amount from about 0.3% to about 0.6% by weight.

The fiber-size composition of the present invention includes a silane coupling agent present in the amount of from about 1.0% to about 3.0% by weight; a PVP film-former present in an amount of from about 4.0% to about 7.0% by weight; a PEG lubricant present in an amount of from about 2.0% to about 3.5% by weight; a polyethyleneimine polyamide salt lubricant present in an amount of from about 0.45% to about 0.70% by weight; acetic acid present in an amount of from about 0.3% to about 0.6% by weight; and the remainder water, the sum of the fiber-size constituents making 100%.

An alternative fiber-size composition includes a silane coupling agent present in the amount of from about 1.0% to about 3.0% by weight; a PVP film-former present in an amount of from about 4.0% to about 7.0% by weight; a polyurethane film-former present in an amount of from about 1.0% to about 4.0% by weight; a PEG lubricant present in an amount of from about 2.0% to about 3.5% by weight; a polyethyleneimine polyamide salt lubricant present in an amount of from about 0.45% to about 0.70% by weight; acetic acid present in an amount of from about 0.3% to about 0.6% by weight; and the remainder water, the sum of the fiber-size constituents making 100%.

It is often necessary to include one or more additives useful to improve fiber wettability, component dispersion, and ease of processing of the fiber-size composition Optionally, the fiber-size composition may include conventional additives such as wetting agents, antioxidants, antifoaming agents, processing aids, antistatic agents, and non-ionic surfactants.

The fiber-size composition may be prepared by combining the ingredients thereof according to any method known to one of ordinary skill in the art. Preferably, the fiber-size composition may be made by blending the individual components of the fiber-size composition with a diluent to form a solution or suspension. Most preferably, the diluent is water.

The sequence of combining the ingredients is not critical to forming a stable fiber-size composition. The following is illustrative of a procedure has been found to give a fiber-size composition that can be applied to glass fiber filaments with good results The components, composition as a stable dispersion having a storage stability of up to about 72 hours at temperatures of from about 10° C. to about 32° C. Although pH of the fiber-size composition is not critical, it is preferred that the final fiber-size composition formed by combining all the aforementioned ingredients having a pH in the range of from about 4 to about 6.5.

The fiber-size composition of the present invention may be applied to the reinforcing fiber material by any suitable method to form a coated reinforcing fiber material. The reinforcing fiber material to which the fiber-size composition of the present invention can be applied may be selected from any reinforcing fiber materials known in the art such as glass fibers, polymer fibers, carbon or graphite fibers, natural fibers and any combination thereof. Preferably, glass fibers are used including soda lime glasses, borosilicate glasses such as E-glass, high-strength glasses such as S-glass, and E-type glasses with lower amounts of boron or boron-free glasses. In addition to boron, such glasses may also be free of moieties such as F₂, TiO₂, and SO₃ and their combinations. As used here, the term “boron/fluorine free” refers to glasses with low amounts or none of these two elements.

The reinforcing fiber material may be in the form of individual filaments, twisted yams, strands or rovings. The sized reinforcing fiber material may be used in continuous or discontinuous form in the manufacture of fiber-reinforced composites. The term “continuous” as used herein with regard to the reinforcing fiber material is intended to include reinforcing fiber materials that are in the form of unbroken filaments, threads, strands, yams or rovings and which may either be sized directly after formation in a continuous fiber-forming operation or which may be formed and wound into packages that can be unwound at a later time to allow application of the fiber-size composition. The term “discontinuous” as used herein with regard to the reinforcing fiber material is intended to include reinforcing fiber materials that have been segmented by chopping or cutting or which are formed from a process designed to form segmented fibers such as a fiber-forming spinner process. The segments of discontinuous reinforcing fiber material that are used in the present invention may vary in length, ranging from about 1 mm to about 25 mm in length.

Accordingly, the fiber-size composition may be applied, for example, to continuous filaments of a reinforcing fiber material immediately after they are formed in an in-line operation, that is, as part of the filament formation process. Alternatively, the fiber-size composition may be applied off-line to unwound strands of reinforcing fiber material that were previously formed and packaged. Also the strands may be cut or chopped in an off-line process. Means for applying the fiber-size composition include, but are not limited to, pads, sprayers, rollers or immersion baths, which allow a substantial amount of the surfaces of the filaments of the reinforcing fiber material to be wetted with the fiber-size composition.

Preferably, the fiber-size composition is applied to a plurality of continuously forming filaments of a reinforcing fiber material as soon as they are formed from a fiber-forming apparatus such as a bushing. The bushing is preferably equipped with small apertures to allow passage of thin streams of a molten reinforcing fiber material. As the streams of molten material emerge from the bushing apertures, each stream is attenuated and pulled downward to form a long, continuous filament. After the filament formation process which includes the application of the fiber-size composition, the continuously forming filaments may then be gathered into strands and chopped or cut in an in-line operation, or they may be gathered into strands for winding into forming packages or doffs after which they may be optionally chopped in an off-line operation. The chopped strands or the forming packages are then dried. Typically, chopped strands are dried in an oven using a temperature ranging from about 50° C. to about 300° C. Typically, forming packages are dried, for example, in a static oven for a period of about 3 hours to about 30 hours at a temperature of about 100-150° C. after which they are ready for use in composite-making operations. Of course, other drying techniques can be used. The glass-fiber composition is typically applied to the fiber in an amount to give about 0.01 to about 7.0 wt % dry solids, preferably in an amount of 0.03 to about 6 wt % dry solids and most preferably in an amount of about 0.1 to about 5 wt % dry solids based on the total weight of dry solids of the fiber-size composition and the glass fibers.

The resulting sized reinforcing fiber material may be utilized to form a composite material. Suitable matrix resins for this purpose may be thermoplastic polymers, thermoset polymers, solution processable polymers, aqueous based polymers, monomers, oligomers, and polymers curable by air, heat, light, x-rays, gamma rays, microwave radiation, dielectric heating, UV radiation, infrared radiation, corona discharge, electron beams, and other similar forms of electromagnetic radiation. Suitable matrix resins include, but are not limited to, polyolefins, modified polyolefins, saturated or unsaturated polyesters, polyacetals, polyamides, polyacrylamides, polyimides, polyethers, polyvinylethers, polystyrenes, polyoxides, polycarbonates, polysiloxanes, polysulfones, polyanhydrides, polyiminesepoxies, polyacrylics, polyvinylesters, polyurethanes, maleic resins, urea resins, melamine resins, phenol resins, furan resins polymer blends, polymer alloys and their mixtures.

The composite formulation may also include one or more conventionally known additives such as coupling agents, compatibilizers, flame retardants, pigments, antioxidants, lubricants, antistats and fillers. Typically, additives are applied in amounts of from 0.1 wt percent to 10 wt percent of the total weight of sized reinforcing fiber and matrix resin, preferably 0.2 wt percent to 7.5 wt percent, and most preferred from 0.25 wt percent to about 5 wt percent.

The process of compounding and molding the sized reinforcing fiber material and the matrix resin to form a composite may be accomplished by any means conventionally known in the art. Such compounding and molding means include, but are not limited to, extrusion, wire coating, blow molding, compression molding, injection molding, extrusion-compression molding, extrusion-injection-compression molding, long fiber injection, and pushtrusion. In a preferred embodiment of the present invention, the chopped fiber strand is coated with the fiber-size composition and is extruded with a polyamide resin matrix to form pellets. These chopped pellets then are suitably injection molded into a desired composite article.

The amount of matrix resin included in the composite is generally about 10% to about 99% by weight, based on the total weight of the composite formulation. Preferably, the percent composition of matrix resin is between about 30% and about 95% by weight. Most preferable is about 60% to about 90% by weight, based on the total weight of the composite.

The fiber-size composition of the present invention provides a coating on the reinforcing fibers that improves compatibility and adhesion with the resin matrix, and results in composites with more desirable properties such as higher short-term and long-term mechanical properties.

The invention illustratively disclosed herein may be practiced in the absence of any element that is not specifically disclosed herein. The following examples are representative, but are in no way limiting as to the scope of this invention.

EXAMPLES

The size composition components according to embodiments of the present invention are set forth in Tables 1-5. TABLE 1 % by Lbs./100 Actual Solids weight gallon of % Active as as Total Size on Material Solids^((a)) received received the Glass A1100 Silane^((b)) 58.000 1.210 10.079 0.04 PVP K15^((c)) 100.000 5.065 42.191 0.32 Peg 400M0^((d)) 100.000 2.171 18.084 0.14 Emery 6760L^((e)) 12.500 0.499 4.157 0.0039 Acetic Acid 100.000 0.330 2.749 D.M. Water 0.000 90.725 755.739 0.50 = Total solids % ^((a))% Active Solids used to calculate predicted size mix solids. ^((b))A-1100 is an amino-propyl-triethoxy-silane coupling agent. ^((c))PVP K15 is a low molecular weight polyvinylpyrrolidone film former ^((d))PEG 400MO is a low molecular weight polyethylene glycol lubricant ^((e))Emery 6760L is a polyethyleneimine polyamide salt lubricant

TABLE 2 % by Lbs./100 Actual Solids weight gallon of % Active as as Total Size on Material Solids^((a)) received received the Glass A1100 Silane^((b)) 58.000 1.452 12.095 0.05 PVP K15^((c)) 100.000 6.078 50.630 0.38 Peg 400M0^((d)) 100.000 2.605 21.700 0.16 Emery 6760L^((e)) 12.500 0.599 4.990 0.0047 Acetic Acid 100.000 0.396 3.299 D.M. Water 0.000 88.870 740.287 0.60 = Total solids % ^((a))% Active Solids used to calculate predicted size mix solids. ^((b))A-1100 is an amino-propyl-triethoxy-silane coupling agent. ^((c))PVP K15 is a low molecular weight polyvinylpyrrolidone film former ^((d))PEG 400MO is a low molecular weight polyethylene glycol lubricant ^((e))Emery 6760L is a polyethyleneimine polyamide salt lubricant

TABLE 3 % by Lbs./100 Actual Solids weight gallon of % Active as as Total Size on Material Solids^((a)) received received the Glass A1100 Silane^((b)) 58.000 1.694 14.11 0.06 PVP K15^((c)) 100.000 7.091 59.068 0.44 Peg 400M0^((d)) 100.000 3.039 25.315 0.19 Emery 6760L^((e)) 12.500 0.699 5.823 0.0055 Acetic Acid 100.000 0.462 3.848 D.M. Water 0.000 87.015 724.835 0.70 = Total solids % ^((a))% Active Solids used to calculate predicted size mix solids. ^((b))A-1100 is an amino-propyl-triethoxy-silane coupling agent. ^((c))PVP K15 is a low molecular weight polyvinylpyrrolidone film former ^((d))PEG 400MO is a low molecular weight polyethylene glycol lubricant ^((e))Emery 6760L is a polyethyleneimine polyamide salt lubricant

TABLE 4 % Lbs./100 Actual Solids by weight gallon of % Active as as Total Size on Material Solids^((a)) received received the Glass A1100 Silane^((b)) 58.000 1.210 10.079 0.04 PVP K15^((c)) 100.000 4.559 37.976 0.28 Hydrosize U6-03^((d)) 30.000 1.69 14.061 0.03 Peg 400M0 (100)^((e)) 100.00 2.171 18.084 0.14 Emery 6760L^((f)) 12.500 0.499 4.157 0.0039 Acetic Acid 100.000 0.330 2.749 D.M. Water 0.000 89.543 745.893 0.50 = Total solids % ^((a))% Active Solids used to calculate predicted size mix solids. ^((b))A-1100 is an amino-propyl-triethoxy-silane coupling agent. ^((c))PVP K15 is a low molecular weight polyvinylpyrrolidone film former ^((d))Hydrosize U6-03 is a polyurethane film former ^((e))PEG 400MO is a low molecular weight polyethylene glycol lubricant ^((f))Emery 6760L is a polyethyleneimine polyamide salt lubricant

TABLE 5 % Lbs./100 Actual Solids by weight gallon of % Active as as Total Size on Material Solids^((a)) received received the Glass A1100 Silane^((b)) 58.000 1.210 10.079 0.04 PVP K15^((c)) 100.000 4.052 33.752 0.25 Hydrosize U6-03^((d)) 30.000 3.38 28.130 0.06 Peg 400M0 (100)^((e)) 100.00 2.171 18.084 0.14 Emery 6760L^((f)) 12.500 0.499 4.157 0.0039 Acetic Acid 100.000 0.330 2.749 D.M. Water 0.000 88.361 736.047 0.50 = Total solids % ^((a))% Active Solids used to calculate predicted size mix solids. ^((b))A-1100 is an amino-propyl-triethoxy-silane coupling agent. ^((c))PVP K15 is a low molecular weight polyvinylpyrrolidone film former ^((d))Hydrosize U6-03 is a polyurethane film former ^((e))PEG 400MO is a low molecular weight polyethylene glycol lubricant ^((f))Emery 6760L is a polyethyleneimine polyamide salt lubricant

Table 6 presents the results of tests conducted on composites formed using Sample 1 and Comparative Samples A and B using a polyamide 6 matrix resin. A direct long fiber processes, pushtrusion, was used. TABLE 6 Sample Comp. Comp. 1 Sample A Sample B Tensile Stress (psi × 10³) 21.31 19.51 18.83 Youngs Modulus (psi × 10⁶) 1.58 1.17 1.14 Tensile Elongation (%) 1.90 1.98 1.97 Flex Stress (psi × 10³) 33.67 33.43 31.93 Youngs Modulus (psi × 10⁶) 1.07 0.87 0.85 Modulus 10-40% (psi × 10⁶) 0.195 0.230 0.219 Displacement at Yield (inches) 0.195 0.230 0.219 Thickness (inches) 0.120 0.121 0.120 IZOD Unotched (ft-lbs) 11.84 16.37 13.98 LOI (%) 72.33 72.47 73.16 Glass content (%) 28 28 27

Table 7 presents the results of tests conducted on composites formed using Sample 2 and Comparative Samples C and D using a polyamide 6,6 matrix resin. A direct long fiber processes, pushtrusion, was used. TABLE 7 Sample Comp. Comp. 2 Sample C Sample D Tensile Stress (psi × 10³) 21.45 20.44 20.56 Youngs Modulus (psi × 10⁶) 1.42 1.20 1.18 Tensile Elongation (%) 1.92 2.07 2.11 Flex Stress (psi × 10³) 35.76 34.68 34.79 Youngs Modulus (psi × 10⁶) 1.21 0.95 0.93 Modulus 10-40% (psi × 10⁶) 0.181 0.212 0.216 Displacement at Yield (inches) 0.181 0.212 0.216 Thickness (inches) 0.119 0.121 0.121 IZOD Unotched (ft-lbs) 10.13 13.20 14.38 LOI (%) 73.43 73.64 73.33 Glass content (%) 27 26 27

Table 8 presents the results of tests conducted on composites formed using Sample 3 and Comparative Samples E and F using a polyamide 6,6 matrix resin. Long fiber pellets were tested. TABLE 8 Sample Comp. Comp. 3 Sample E Sample F Tensile Stress (psi × 10³) 37.28 34.55 Youngs Modulus (psi × 10⁶) 2.79 2.74 Tensile Elongation (%) 2.00 1.90 Flex Stress (psi × 10³) 57.48 55.92 Youngs Modulus (psi × 10⁶) 2.23 2.37 Modulus 10-40% (psi × 10⁶) 0.164 2.35 Displacement at Yield (inches) 0.164 0.164 Thickness (inches) 0.120 0.164 IZOD Unotched (ft-lbs) 26.60 25.26 LOI (%) 49.84 48.58 Glass content (%) 50 51 The invention of this application has been described above both generically and with regard to specific embodiments. Although the invention has been set forth in what is believed to be the preferred embodiments, a wide variety of alternatives known to those of skill in the art can be selected within the generic disclosure. The invention is not otherwise limited, except for the recitation of the claims set forth below. 

1. A fiber-size composition comprising: at least about 4% by weight of a polyvinylpyrrolidone film former having a molecular weight in the range of about 10,000 to about 70,000; at least one lubricant; and a coupling agent.
 2. The fiber-size composition according to claim 1 wherein said lubricant is polyethylene glycol.
 3. (canceled)
 4. The fiber-size composition of claim 1 further comprising a polyethyleneimine polyamide salt lubricant
 5. The fiber-size composition of claim 1 wherein said coupling agent is a silane coupling agent.
 6. A fiber-size composition comprising: at least about 4% by weight of a polyvinylpyrrolidone film former at least one lubricant: a coupling agent, and further comprising a polyurethane.
 7. A fiber-size composition comprising: from about 1.0% to about 3.0 by weight of a silane coupling agent; from about 4.0% to about 7.0% by weight of a polyvinylpyrrolidone film-former; from about 1.0% to about 4.0% by weight of a polyurethane film-former, from about 2.0% to about 3.5% by weight of a polyethylene glycol lubricant; from about 0.45% to about 0.70% by weight of a polyethyleneimine polyamide salt lubricant; from about 0.3% to about 0.6% by weight of an acetic acid; and the remainder water, the sum of the fiber-size constituents making 100%.
 8. A reinforcing fiber coated with the fiber-size composition of claim
 1. 9. The reinforcing fiber of claim 8 wherein said fiber is an E-glass fiber.
 10. A compounding formulation comprising the reinforcing fiber of claim 8 and a matrix resin.
 11. The compounding formulation of claim 10 wherein said matrix resin is selected from the group consisting of polyolefins, polyesters, polyacetals, polyamides, polyacrylamides, polyimides, polyethers, polyvinylethers, polystyrenes, polyoxides, polycarbonates, polysiloxanes, polysulfones, polyanhydrides, polyimines, epoxies, polyacrylics, polyvinylesters, polyurethane, maleic resins, urea resins, melamine resins, phenol resins, furan resins, polymer blends, polymer alloys, and mixtures thereof.
 12. The compounding formulation of claim 10 wherein said matrix resin is a polyamide.
 13. A composite article formed from the compounding formulation of claim
 10. 14. A method of preparing reinforcing fibers comprising: a) preparing a fiber-size composition comprising: at least about 4% by weight of a polyvinylpyrrolidone film former having a molecular weight in the range of about 10,000 to about 70.000; at least one lubricant; and a coupling agent; b) contacting fibers with said fiber-size composition; and c) allowing said fiber-size composition to solidify on said fibers to form said reinforcing fibers.
 15. The method of preparing reinforcing fibers according to claim 14 wherein said fibers are glass fibers.
 16. A method of preparing reinforcing fibers comprising: a) preparing a fiber-size composition comprising: at least about 4% by weight of a polyvinylpyrrolidone film former; at least one lubricant; and a coupling agent; b) contacting fibers with said fiber-size composition; and c) allowing said fiber-size composition to solidify on said fibers to form said reinforcing fibers; wherein said fiber-size composition further comprises a polyurethane film-former; and a second lubricant and acetic acid.
 17. The method of claim 16 wherein said fiber-size composition comprises from about 1.0% to about 3.0 by weight of a silane coupling agent; from about 4.0% to about 7.0% by weight of a polyvinylpyrrolidone film-former; from about 1.0% to about 4.0% by weight of a polyurethane film-former; from about 2.1% to about 3.5% by weight of a polyethylene glycol lubricant; from about 0.45% to about 0.70% by weight of a polyethyleneimine polyamide salt lubricant; from about 0.3% to about 0.6% by weight of an acetic acid; and the remainder water, the sum of the fiber-size constituents making 100%.
 18. The method of preparing reinforcing fibers according to claim 15 wherein said glass fibers are essentially boron-free glass fibers.
 19. A method of preparing a composite formulation comprising the step of combining said reinforcing fibers prepared according to the method of claim 14 with a matrix resin to form said composite formulation.
 20. A method of preparing a composite article comprising the step of forming said composite formulation formed in claim 19 into said composite article. 